They don't provide a simple email address for that sort of thing. I think it's because they would be deluged with reports, many of which would turn out to be developer bugs or misunderstandings.

You can always submit a paid tech support request with your bug report explained. If it really is a bug, they should refund your payment.

But, better to post it publicly here on the forum. The clearer you explain the bug, and the easier you make it to reproduce the bug (sample API call, parameters/conditions of when the bug appears, etc.) the more likely either another developer will help you out, or an eBay developer support rep will have a closer look and put it right into their bug trac queue.

Clearly, you don't understand how eBay work... you can't report a bug because their system is "flawless" - why else would they prevent any developer feedback unless you pay a ridiculous amount for support hours??? Even when all you want to do is tell them something is wrong... grrrrrrrrrrrr.

I guess all us lowly developers can do is wait for them to realise their system is flawed.

If you come across a bug, just post it here on the forums, as I suggested earlier. There are a number of us old-timers floating around here on the forums, and some eBay support presence as well. Someone will address it, especially if you are very articulate about how you encountered the bug.